hawkinson



March 10, 1964 R. P. HAwKlNsoN 3,123,865

i TIRE RETREADING MoLD Filed Jan. :51, 1982 2 Shee'S-Shee' 1 F104 I' Fm. ,26 2/' IIIIIII I I I I IIIIIII I I I I L llllIII I I I I I JIIIIII I I I I I I IIVVENT RAYMoNo R HAwK/Nso/v .A T TO'QNE YS March 10, 1964 R. P. HAwKlNsoN TIRE RETREADING MoLD 2 Sheets-Sheet 2 Filed Jan. 31, 1962 INVENTOR. RAYMOND R HAwK/Nsov O/mo, 5

A T ToRNE Ys United States Patent O 3,123,865 A 'IIRE RETREADING MOLD Raymond P. Hawkinson, Minneapolis, Minn., assignor to Paul E. Hawkinson Company, Minneapolis, Minn., a corporation of Minnesota Filed Jan. 31, 1962, Ser. No. 170,034 2 Clajms. (Cl. 18-38) My invention relates to tire retreading apparatus and more particularly to tire retreading molds.

Still more Specifically my invention relates to improvements in band-type molds, that is molds having a relatively flat cross section for the application of top caps, as distinguished from molds having an arcuate cross section for application of full retreads.

Even more specifically, my invention relates to top Cap molds of the type utilizing a cylinder-like sheet metal mold having received therein a cast metal matrix formed from a plurality of segmental Sections in end-to-end relationship; and the primary object of my invention is the provision of novel heating means for the confining flanges of said matrix.

A further object of my invention is the provision of a retreading mold of the type immediately above described in which the heating means for the confining fianges locks the segmental Sections in annular form, independently of the sheet metal mold, whereby not only to impart greater rigidity to the overall mold but also to permit assemblage of the matrix Sections exteriorly of the sheet metal mold for subsequent axial insertion thereinto or, alternately, axial removal therefrom.

A further object of my invention is the provision of a device of the class above described which is highly efiicient in its operation and which adds but a minimum of weight to the overall mold.

A still further object of my invention is the provision of a device of the class above described which is relatively inexpensive to produce and which is rugged and durable.

The above and still further objects of my invention will become apparent from the following detailed specification, appended claims and attached drawings.

Referring to the drawings wherein like characters indicate like parts throughout the several views:

FIG. 1 is a view in end elevation of my novel retreading mold, some parts being broken away;

FIG. 2 is a view in side elevation of the structure of FIG. 1, on an enlarged scale;

FIG. 3 is a view in perspective of one of the matrix Sections utilized in my invention;

FIG. 4 is an enlarged detail of a portion of FIG. 1, as seen from the line 4-4 of FIG. 2, Some parts being broken away and some parts shown in section.

FIG. 5 is an enlarged fragmentary transverse section taken on the line 5-5 of FIG. 1;

FIG. 6 is an enlarged fragmentary section taken on the line 6 6 of FIG. 4; and

FIG. 7 is' an enlarged fragmentary section taken on the line 7- 7 of FIG. 4.

Referring with greater particularity to the drawings, the numeral 1 indicates a cylinder-like mold element formed from sheet steel. The opposite marginal edges of the mold element 1 are bent radially outwardly at right angles to provide rails 2, the opposite side surfaces 3 of ice which are in parallel planes. Snugly received within the cylindrical mold element 1 is an annular matrix 4, preferably and as shown formed from a plurality of segmental matrix Sections 5 in end-to-end relationship. The matrix Sections 5 may be formed from an aluminum alloy or other suitable metal having high heat conductivity.

As shown, a tubular metallic heating coil 6 is wound spirally about the radially outer surface 7 of the mold element 1, intermediate the rails 2, and is secured thereto by soldering or the like as indicated at 8. Preferably and as shown the radial depth of the heating coil 6 is less than that of the rails 2. Consequently the coils 6 are completely protected as the entire structure is rolled along a fioor or the like on said rails 2.

At its opposite marginal edges, the matrix 4 is formed to define laterally spaced radially inwardly projecting unbroken tread material-confining fianges 9. The flanges 9 have flat parallel outer surfaces 10 which are in alignment with and form a continuation of the parallel flat surfaces 3 of the rails 2.

The radially intermediate portions of each of the spaced tread materal-confining flanges 9 of each of the matrix Sections 5 are provided with an arcuat-e groove 11 which are in circumferential alignment with the grooves 11 of the adjacent section 5 and which collectively define endless annular channels 12 which are concentric with the matrix 4 and the mold element 1 and which open outwardly through the outer surfaces 10 of said matrix 4. Snugly received within each of the channels 12 is a tubular metalic heating conduit 13, opposite ends 14, 15 of which are connected to inlet and outlet pipes 14', 15' through the medium of suitable unions 16. As shown particularly in FIG. 6, the heating tubes of conduits 13 are completely received within their respective channels 12 and the metal from which the matrix Sections 5 are formed is peened at circumferentially spaced points as indicated at 17 to positively lock the tubes 13 within said channels 12 against accidental displacement, whereby to insure heat transfer throughout said radial annular fianges 9.

As above indicated, when the tubular coils 13 are locked within their respective channels 12, the Sections 5 are retained in an annular position, irrespective of the mold element 1. Hence the matrix 4 may be completely formed externally of the mold element 1 if desired and entered thereinto and removed therefrom axially. In practice, headed screws 18 are provided to positively lock the matrix 4 within the cylinder-like mold 1.

My invention has been thoroughly tested and found to be completely satisfactory for the accomplishment of the above objects, and while I have shown and described a preferred embodiment, I wish it to be specifically understood that the same is capable of modification without departure from the spirit and scope of the appended claims.

What I claim is:

1. In a device of the class described,

(a) a cylinder-like Sheet metal mold element having its opposite side edge portions extending radially outwardly to form marginal rails having parallel outer side faces,

(b) an annular matrix received within said mold element and comprising a plurality of cast metal matrix Sections in end-to-end abutting relationship,

(c) Said matrix at its opposite marginal sides defining a laterally spaced radially inwardly projecting endless tread material-confining flanges having parallel outer faces which are in general alignment with the outer faces of said rails,

(d) the radially intermediate outer face portions of the fianges of each of said matrix Sections being fonned to define arcuate grooves which are in circuniferential communication to collectively define endless oppositely open annular Channels,

(e) and annular metallic heating tubes fixedly secured within said channels and retaining said matrix sections in annular end-to-end abutting form independently of said cylinder-like mold element.

2. The structure defined in claim 1 in which said annular metallic heating tubes are completely received with 15 2370346 5 together by this heating tube.

References Cited in the file of this patent UNITED STATES PATENTS Hawkinson Nov. 24, 1953 2,710,424 Kraft et al June 14, 1955 2,813,304 Hawkinson Nov. 19, 1957 2,886,851 Strickler et al. May 19, 1959 Fannen Feb. 7, 1961 

1. IN A DEVICE OF THE CLASS DESCRIBED, (A) A CYLINDER-LIKE SHEET METAL MOLD ELEMENT HAVING ITS OPPOSITE SIDE EDGE PORTIONS EXTENDING RADIALLY OUTWARDLY TO FORM MARGINAL RAILS HAVING PARALLEL OUTER SIDE FACES. (B) AN ANNULAR MATRIX RECEIVED WITHIN SAID MOLD ELEMENT AND COMPRISING A PLURALITY OF CAST METAL MATRIX SECTIONS IN END-TO-END ABUTTING RELATIONSHIP, (C) SAID MATRIX AT ITS OPPOSITE MARGINAL SIDES DEIFINING LATERALLY SPACED RADIALLY INWARDLY PROJECTING ENDLESS TREAD MATERIAL-CONFINING FLANGES HAVING PARALLEL OUTER FACES WHICH ARE IN GENERAL ALIGNMENT WITH THE OUTER FACES OF SAID RAILS, (D) THE RADIALLY INTERMEDIATE OUTER FACE PORTIONS OF THE FLANGES OF EACH OF SAID MATRIX SECTIONS BEING FORMED TO DEFINE ARCUATE GROOVES WHICH ARE IN CIRCUMFERENTIAL COMMUNICATION TO COLLECTIVELY DEFINE ENDLESS OPPOSITELY OPEN ANNULAR CHANNELS, 